TW202244006A - Infrared absorbing particles, infrared-absorbing particle dispersion liquid, infrared-absorbing particle dispersion material, infrared-absorbing laminate transparent substrate, and infrared-absorbing transparent substrate - Google Patents

Abstract

An infrared-absorbing particle, which is an infrared-absorbing particle containing a composite tungsten oxide particle, the above-mentioned composite tungsten oxide particle has a hexagonal crystal structure, and is formed by the general formula M _x W _y O _z (wherein, M is selected from Cs, One or more elements of Rb, K, Tl, Ba, Ca, Sr, Fe, W is tungsten, O is oxygen, 0.25≦x/y≦0.39, 2.70≦z/y≦2.90) the composite tungsten oxide particles of matter.

Description

Infrared Absorbing Particles, Infrared Absorbing Particle Dispersion, Infrared Absorbing Particle Dispersion, Infrared Absorbing Interlayer Transparent Substrate, Infrared Absorbing Transparent Substrate

The present invention relates to infrared-absorbing particles, infrared-absorbing particle dispersion, infrared-absorbing particle dispersion, infrared-absorbing interlayer transparent substrate, infrared-absorbing transparent substrate.

As a method of removing and reducing heat components from external light sources such as sunlight and light bulbs, heat ray reflective glass has been conventionally formed by forming a film made of a material that reflects infrared rays on the glass surface. Furthermore, metal oxides such as FeO _x , CoO _x , CrO _x , and TiO _x , and metal materials such as Ag, Au, Cu, Ni, and Al are used as materials.

However, these metal oxides and metal materials have the property of reflecting or absorbing visible light in addition to infrared rays which greatly contribute to the thermal effect, so there is a problem that the visible light transmittance of the heat ray reflecting glass decreases. In particular, substrates used in building materials, vehicles, telephone boxes, etc. require high transmittance in the visible light region, so when using materials such as the above-mentioned metal oxides, the film thickness must be very thin. Therefore, a method of forming a film using a thin film with a film thickness of about 10 nm is employed using a physical film forming method such as spray sintering, CVD, sputtering, or vacuum deposition.

However, these film-forming methods require large-scale equipment and vacuum equipment, and have difficulties in productivity and large-area enlargement, and have disadvantages in that film production costs increase. In addition, if these materials are used to improve the solar shielding property, the reflectance of light in the visible light region tends to increase at the same time, and it also has the disadvantage of imparting a dazzling appearance like a mirror and impairing the appearance.

In order to improve such a problem, it is considered that a film having a low reflectance of light in the visible region and a high reflectance in the infrared region, which are physical properties of the film, is required.

Antimony tin oxide (hereinafter, abbreviated as ATO) and indium tin oxide (hereinafter, abbreviated as ITO) are known as materials having high visible light transmittance and excellent solar shielding function. These materials do not impart a dazzling appearance due to their relatively low reflectance of visible light. However, since the plasmon frequency is in the near-infrared region, reflection and absorption effects are still insufficient for light in the near-infrared region, which is closer to the visible light region. Furthermore, since these materials have low sunlight shielding power per unit weight, in order to obtain a high shielding function, there exists a problem that the usage-amount increases and a cost rises.

Furthermore, examples of infrared shielding film materials having a sunlight shielding function include films obtained by slightly reducing tungsten oxide, molybdenum oxide, and vanadium oxide. These films are materials used as so-called electrochromic materials, but they are transparent in a fully oxidized state, and when reduced electrochemically, absorb from the long-wavelength visible region to the near-infrared region.

In Patent Document 1, a heat ray shielding glass is proposed, which is characterized in that a first dielectric film as a first layer on the side of the substrate is provided on a transparent glass substrate, and a first dielectric film is provided as a first layer on the first layer. 2 layers of composite tungsten oxide films containing at least one metal element selected from the group consisting of IIIa, IVa, Vb, VIb and VIIb of the periodic table, on the second layer as the third layer of the second dielectric film.

In Patent Document 2, an ultraviolet heat ray shielding glass is proposed, which is characterized in that, on a transparent glass substrate, a first transparent dielectric film is provided as a first layer on the substrate side, and the first transparent dielectric film The electrode film contains: an oxide having ultraviolet blocking performance comprising at least one selected from the group consisting of zinc, cerium, titanium, and cadmium, and a trace amount of A composite oxide of a metal element, in which a second transparent dielectric film is provided as a second layer on the first layer, and a compound containing a group IIIa and IVa selected from the periodic table is provided as a third layer on the second layer. , a composite tungsten oxide film of at least one metal element in the group formed by Vb, VIb, and VIIb, and a third transparent dielectric film as a fourth layer is provided on the third layer.

In Patent Document 3, a heat ray shielding glass is proposed, which is characterized in that on a transparent substrate, as the first layer on the side of the substrate, a glass containing glass selected from the group IIIa, IVa, Vb, and VIb of the periodic table is provided. A composite tungsten oxide film of at least one metal element in the group formed with Group VIIb, and a transparent dielectric film as a second layer is provided on the first layer.

Patent Document 4 proposes a method of forming a tungsten oxide film, which is characterized in that the method of forming a tungsten oxide film on a substrate is performed by sputtering in an atmosphere containing carbon dioxide using a target made of tungsten. According to such a film forming method, it is disclosed that a tungsten oxide film having high heat-shielding properties and uniform in-plane optical properties can be stably produced.

For example, as described in Patent Document 1 to Patent Document 4, a sputtering method has conventionally been used as a method for producing an infrared shielding layer containing a tungsten compound. However, such a physical film-forming method requires large-scale equipment and vacuum equipment, which is problematic from the viewpoint of productivity, and even if it is technically possible to increase the area, there is a problem that the production cost of the film increases.

Therefore, the applicant disclosed in Patent Document 5 that the light in the visible light region is transmitted, and the light in the infrared region is absorbed by the tungsten oxide particles expressed by the general formula W _y O _x , and the composite tungsten expressed by the general formula M _x W _y O _z An infrared shielding material particle dispersion in which oxide particles are dispersed in a medium, an infrared shielding body, a method for producing infrared shielding material particles, and an infrared shielding material particle.

In addition, the present applicant disclosed in Patent Document 6 that light in the visible light region transmits and absorbs light in the infrared region as tungsten oxide particles expressed by the general formula W _y O _x and expressed by the general formula M _x W _y O _z The manufacturing method of the tungsten oxide particle for solar shielding body formation of the composite tungsten oxide particle, and the tungsten oxide particle for solar shielding body formation.

As disclosed in Patent Document 5 and Patent Document 6, the solar shielding body containing fine particles of tungsten oxide does not require a large-scale apparatus or vacuum equipment such as a physical film-forming method, and has high productivity and can be produced at low cost. In addition, from the viewpoint of characteristics as a solar shielding body, a solar shielding body containing tungsten oxide fine particles or the like can further improve the light transmittance in the visible light region without lowering the infrared shielding performance. [Prior Art Literature] [Patent Document]

Patent Document 1: Japanese Patent Application Laid-Open No. 8-12378 Patent Document 2: Japanese Patent Application Laid-Open No. 8-59301 Patent Document 3: Japanese Patent Application Laid-Open No. 8-283044 Patent Document 4: Japanese Patent Application Laid-Open No. H10-183334 Patent Document 5: Japanese Patent No. 4096205 Patent Document 6: Japanese Patent No. 4626284

[Problem to be Solved by the Invention]

However, optical members (films, resin sheets, etc.) containing conventionally used tungsten oxide fine particles represented by the general formula W _y O _x , composite tungsten oxide fine particles represented by the general formula M _x W _y O _z exhibit The blue color characteristic of tungsten oxide. Therefore, a lighter color is required depending on the application.

In addition, when the infrared absorbing material is used, it may be placed in a high-temperature and high-humidity environment due to heat from sunlight or the like or moisture in the atmosphere. Therefore, an infrared absorbing material is also required to suppress a decrease in infrared absorbing properties (solar shielding properties) even when placed in a high-temperature, high-humidity environment, that is, to be excellent in weather resistance.

In view of the above-mentioned problems of the prior art, an object of one aspect of the present invention is to provide infrared-absorbing particles that are light blue in color and excellent in weather resistance and infrared-absorbing properties. [Technical means to solve the problem]

In one aspect of the present invention, an infrared-absorbing particle is provided, which is an infrared-absorbing particle containing composite tungsten oxide particles. The above-mentioned composite tungsten oxide particle has a hexagonal crystal structure, and is represented by the general formula M _x W _y O _z ( Among them, M is one or more elements selected from Cs, Rb, K, Tl, Ba, Ca, Sr, Fe, W is tungsten, O is oxygen, 0.25≦x/y≦0.39, 2.70≦z/y ≦2.90) the particles of composite tungsten oxide. [Effect of Invention]

In one aspect of the present invention, it is possible to provide infrared-absorbing particles that are light blue in color and excellent in weather resistance and infrared-absorbing properties.

Details of the infrared-absorbing particles, infrared-absorbing particle dispersion, infrared-absorbing particle dispersion, infrared-absorbing interlayer transparent substrate, and infrared-absorbing transparent substrate according to one embodiment of the present disclosure (hereinafter referred to as "this embodiment") will be described below. example. In addition, the present invention is not limited to these illustrations, and all changes within the meaning and range equivalent to the claims indicated by the claims are also included.

Hereinafter, for the present embodiment, 1. infrared absorbing particles, 2. method for producing infrared absorbing particles, 3. infrared absorbing particle dispersion, 4. infrared absorbing particle dispersion, 5. infrared absorbing interlayer transparent substrate, 6. . Infrared absorbing transparent substrate, 7. Physical properties will be described in order. 1. Infrared Absorbing Particles The infrared absorbing particles according to this embodiment can contain composite tungsten oxide particles. In addition, the infrared-absorbing particles of the present embodiment can also be composed only of composite tungsten oxide particles, but even in this case, inclusion of unavoidable impurities is not excluded.

As the composite tungsten oxide particles, composite tungsten oxide particles represented by the general formula M _x W _y O _z can be used.

The M element in the above general formula may be one or more elements selected from Cs, Rb, K, Tl, Ba, Ca, Sr, and Fe, W may be tungsten, and O may be oxygen. x, y, z can satisfy 0.25≦x/y≦0.39, 2.70≦z/y≦2.90.

The above composite tungsten oxide particles may have a hexagonal crystal structure.

(Composition, Crystal, and Lattice Constant of Composite Tungsten Oxide Particles) In the above general formula of composite tungsten oxide particles, the value of x/y representing the addition amount of the element M is preferably 0.25 or more and 0.39 or less, more preferably Above 0.25 and below 0.32. This is because when the value of x is not less than 0.25 and not more than 0.39, composite tungsten oxide particles of hexagonal crystals are easily obtained, and the infrared absorption effect is sufficiently exhibited. Infrared-absorbing particles may contain precipitates of tetragonal crystals and orthorhombic crystals represented by M _0.36 WO _3.18 (Cs ₄ W ₁₁ O ₃₅ , etc.) in addition to hexagonal composite tungsten oxide particles. Affects the infrared absorption effect. It is considered that the value of x/y of the composite tungsten oxide particles is theoretically 0.33, so that the added M element is arranged in all the hexagonal voids.

In addition, the value of z/y in the above general formula is preferably 2.70≦z/y≦2.90. By setting the value of z/y to 2.70 or more, it is possible to obtain infrared-absorbing particles that are light blue and excellent in weather resistance and infrared-absorbing properties. In addition, the light transmittance at a wavelength of 850 nm, for example, can also be increased by setting the value of z/y to 2.70 or more. With the increasing functionality of automobiles, in-vehicle devices and sensors for control using infrared communication waves are widely used. In order to improve the control accuracy of such various in-vehicle devices and the detection accuracy of sensors, it is also required to design high light transmittance at a wavelength of 850 nm. The infrared-absorbing particles of the present embodiment are excellent in light transmittance at a wavelength of 850 nm as described above, and therefore, the infrared-absorbing particle dispersion using the infrared-absorbing particles, etc., is placed in openings such as windows, etc. Control, sensor detection, improve accuracy.

By setting the value of z/y to 2.90 or less, the absorption and reflection characteristics in the infrared region are improved, and thus a particularly sufficient amount of free electrons can be generated to efficiently form infrared-absorbing particles.

In addition, in the composite tungsten oxide particles, some oxygen may be substituted by other elements. Examples of such other elements include nitrogen, sulfur, and halogen.

The composite tungsten oxide particles preferably have a hexagonal crystal structure. This is because when the composite tungsten oxide particles have a hexagonal crystal structure, the transmittance of light in the visible light region of the composite tungsten oxide particles, the infrared absorbing particles comprising the composite tungsten oxide particles, and the light transmittance in the near infrared region Absorption is particularly enhanced.

Moreover, if one or more elements selected from Cs, Rb, K, Tl, Ba, Ca, Sr, and Fe are used as the M element, hexagonal crystals are likely to be formed. Therefore, the M element preferably contains one or more elements selected from Cs, Rb, K, Tl, Ba, Ca, Sr, and Fe.

The lattice constant of the composite tungsten oxide particles is not particularly limited. For example, the a-axis is preferably 7.3850 Å to 7.4186 Å, and the c-axis is preferably 7.5600 Å to 7.6240 Å. Infrared-absorbing particles including composite tungsten oxide particles may be pulverized to form a desired particle diameter as described later, and the lattice constants of the composite tungsten oxide particles before and after pulverization preferably satisfy the above-mentioned range. (about particle size) The particle size of the infrared-absorbing particles according to the present embodiment can be selected according to the purpose of use of the infrared-absorbing particles, infrared-absorbing particle dispersion liquid, infrared-absorbing particle dispersion, infrared-absorbing interlayer transparent substrate, and infrared-absorbing transparent substrate. limited.

The average dispersed particle diameter of the infrared absorbing particles is preferably, for example, from 1 nm to 800 nm, more preferably from 1 nm to 400 nm. This is because when the average dispersed particle size is 800 nm or less, the strong infrared absorption ability of the infrared absorbing particles can be exhibited, and when the average dispersed particle size is 1 nm or more, industrial production is easy.

In particular, when the average dispersed particle diameter is 400 nm or less, the infrared absorbing film and the molded article (plate, sheet) can avoid becoming grayish in which the transmittance decreases monotonously. In addition, by setting the average dispersed particle size to 400 nm or less, when the infrared absorbing particle dispersion liquid is used to form an infrared absorbing particle dispersion or the like, fogging can be particularly suppressed and visible light transmittance can be improved.

When the infrared absorbing particle dispersion or the like is used for applications requiring light transparency in the visible light region, the infrared absorbing particles preferably have an average dispersed particle diameter of 40 nm or less. Here, the average dispersed particle size is a 50% volume cumulative particle size measured using DLS-8000 manufactured by Otsuka Electronics Co., Ltd. using the dynamic light scattering method as a principle. This is because if the infrared-absorbing particles have an average dispersed particle diameter of less than 40 nm, the scattering of light by Mie scattering and Rayleigh scattering of the infrared-absorbing particles can be sufficiently suppressed, and the visibility of light in the visible light region can be maintained. high while efficiently maintaining transparency. When used in applications requiring transparency, such as windshields for automobiles, the average dispersed particle size of the infrared absorbing particles is more preferably 30 nm or less, more preferably 25 nm or less, in order to further suppress scattering.

The particle size of the composite tungsten oxide particles related to the infrared absorbing particles described above can be determined from the composite tungsten oxide particles, the infrared absorbing film manufactured using the dispersion, the infrared absorbing particle dispersion, the infrared absorbing transparent substrate, the infrared absorbing The purpose of use of the interlayer transparent base material is appropriately selected, and is not particularly limited. The particle size of such composite tungsten oxide particles is preferably not less than 1 nm and not more than 800 nm. In addition, when transparency is important, the particle size of the composite tungsten oxide particles is preferably 200 nm or less, more preferably 100 nm or less. This is because if the particle size is large, light in the visible region with a wavelength of 380nm to 780nm is scattered by geometric scattering or Mie scattering, and the appearance of the infrared absorbing material becomes cloudy glass, making it difficult to obtain clear transparency. When the particle size is 200 nm or less, the above-mentioned scattering is reduced, and it becomes a Rayleigh scattering region. In the Rayleigh scattering region, scattered light decreases in proportion to the 6th power of the particle diameter, and therefore the scattering decreases and the transparency improves as the particle diameter decreases. Furthermore, when the particle diameter is 100 nm or less, scattered light becomes very small, which is preferable. As mentioned above, if the particle size is 800nm or less, the excellent infrared absorption properties brought by the composite tungsten oxide particles according to the present embodiment can be exhibited, and this is because if the particle size is 1nm or more, industrial manufacturing easy.

The particle diameter here can be calculated by measuring the particle diameters of a plurality of particles using a transmission electron microscope (TEM) or the like, for example, in a state where composite tungsten oxide particles are dispersed. In addition, since the composite tungsten oxide particle is generally amorphous, the diameter of the smallest circle circumscribing the particle can be made the particle diameter of the particle. For example, when measuring the particle diameters of a plurality of particles for each particle as described above using a transmission electron microscope, it is preferable that the particle diameters of all the particles satisfy the above range. The number of particles to be measured is not particularly limited, but is preferably 10 or more and 50 or less, for example. (About color) The color tone of the infrared absorbing particles of the present embodiment when calculating only the light absorption by the infrared absorbing particles preferably satisfies b ^* >0 in the L ^* a ^* b ^* color system.

This is because the hue at the time of calculating the light absorption by only the infrared absorbing particles can be light blue by satisfying b ^* >0 in the L ^* a ^* b ^* color system.

Calculating the light absorption by infrared absorbing particles only means that when evaluating, the measurement of the blank is also performed, and the evaluation result of the blank is subtracted from the evaluation result of the infrared absorbing particles, thereby eliminating the unit used in the measurement. The influence of reflection of light brought by etc. (about covering) The infrared absorbing particles can also be surface-treated for the purposes of surface protection, durability improvement, oxidation prevention, and water resistance improvement. The specific content of the surface treatment is not particularly limited. For example, the surface of the infrared-absorbing particles of the present embodiment can be coated with a compound containing one or more atoms selected from Si, Ti, Zr, and Al. That is, the infrared absorbing particles can be coated with the above compound. In this case, examples of the compound containing one or more atoms selected from Si, Ti, Zr, and Al include one or more atoms selected from oxides, nitrides, carbides, and the like. 2. Manufacturing method of infrared absorbing particles According to the method for producing infrared-absorbing particles of the present embodiment, the infrared-absorbing particles described above can be produced. Therefore, descriptions of matters already described are omitted.

The inventors of the present invention have studied a method for producing infrared-absorbing particles having a light blue color and excellent weather resistance and infrared-absorbing properties.

In addition, the term "weather resistance" here means that, for example, a dispersion of infrared-absorbing particles can be suppressed from reducing the sun-shielding properties when placed in a high-temperature, high-humidity environment.

As a result, they have found that infrared-absorbing particles capable of solving the above-mentioned problems can be obtained by performing the following first heat treatment step and second heat treatment step on predetermined raw materials, and completed the present invention.

The first heat treatment step (oxidizing gas heat treatment step) is a step of performing heat treatment in an atmosphere of a first gas containing at least an oxygen source.

The second heat treatment step (non-oxidizing gas heat treatment step) is a step of performing heat treatment in an atmosphere containing one or more second gases selected from reducing gases and inert gases.

In addition, the order of carrying out the first heat treatment step and the second heat treatment step is not particularly limited, for example, the second heat treatment step may be carried out after the first heat treatment step is carried out, and the first heat treatment step may be carried out after the second heat treatment step is carried out.

Here, the heat treatment conditions will be described in detail after the raw material powders to be subjected to the heat treatment are described. (1) Raw material powder Here, the so-called raw material powder is a mixed powder selected from tungstic acid (H ₂ WO ₄ ) or a mixture of tungstic acid and a compound containing M element, and tungstic acid (H ₂ WO ₄ ) or a mixture of tungstic acid and One or more dry powders of mixed solutions of solutions containing M elements.

The above tungstic acid mixture is a mixture of tungstic acid (H ₂ WO ₄ ) and tungsten oxide.

The above-mentioned mixed powder and dry powder will be described. (mixed powder) As the raw material powder, mixed powder can be used as described above. As the mixed powder, for example, a mixed powder of tungstic acid and a compound containing an M element, or a mixed powder of a mixture of tungstic acid and a compound containing an M element can be used.

Here, tungstic acid (H ₂ WO ₄ ) used for the raw material powder is not particularly limited as long as it is a raw material powder that becomes an oxide by firing. In addition, any of W ₂ O ₃ , WO ₂ , and WO ₃ can be used as the tungsten oxide used for the tungstic acid mixture.

In addition, the compound containing the M element for adding the M element by mixing with tungstic acid or a tungstic acid mixture is preferably one or more selected from oxides, hydroxides, and carbonates. Therefore, the compound containing the M element is preferably one or more selected from the oxide of the M element, the hydroxide of the M element, and the carbonate of the M element.

In addition, the M element is preferably one or more elements selected from Cs, Rb, K, Tl, Ba, Ca, Sr, and Fe.

The mixing of tungstic acid (H ₂ WO ₄ ) or a mixture of tungstic acids and the compound containing M element may be performed by using a commercially available mill, kneader, ball mill, sand mill, paint shaker, etc. (mixing process). (Dry powder) In addition, as a raw material powder, the dry powder of the mixed solution of tungstic acid ( _{H2WO4 )} or a mixture of tungstic acid and the solution containing M element can be used.

Regarding tungstic acid and a mixture of tungstic acid, the mixed powder was used for the description, and the description is omitted here.

The solution containing the M element is preferably one or more selected from an aqueous solution of a metal salt of the M element, a colloidal solution of a metal oxide of the M element, and an alkoxy solution of the M element.

The kind of the metal salt used for the aqueous solution of the metal salt of the M element is not particularly limited, and examples thereof include nitrates, sulfates, chlorides, and carbonates.

In addition, the drying temperature and time when preparing the dry powder are not particularly limited.

The raw material powder preferably contains tungsten and M element in a ratio corresponding to the target composition. For example, the raw material powder preferably contains M element (M) and tungsten (W) contained in the raw material powder so that M/W is 0.25 to 0.39 in molar ratio. (2) Heat treatment process As already described, the method for producing infrared-absorbing particles according to the present embodiment can include a first heat treatment step of heat-treating the raw material powder, and a second heat treatment step. (2-1) The first heat treatment process The first heat treatment step (oxidizing gas heat treatment step) is a step of performing heat treatment in an atmosphere of a first gas containing at least an oxygen source.

The gas of the oxygen source is not particularly limited, but is preferably at least one selected from oxygen, air gas, and water vapor.

The gas other than the oxygen source of the first gas is not particularly limited, and may contain an inert gas, for example. The inert gas is not particularly limited, and one or more gases selected from nitrogen, argon, helium, and the like can be used.

The concentration of the oxygen source in the first gas is not particularly limited as long as it is appropriately selected according to the heat treatment temperature and the amount of heat treatment. If it is excessively oxidized, the infrared absorption function may be reduced, so it is preferably a concentration that oxidizes only the surface of the particles. .

The temperature during the heat treatment is not particularly limited as long as it is appropriately selected according to the amount of the raw material powder to be heat-treated. For example, it is preferably 400°C or higher and 850°C or lower.

By performing the oxidation treatment in the first heat treatment step, for example, the surface of the composite tungsten oxide particle can be oxidized, and polaron absorption is prevented. By performing the first heat treatment step, the transmittance of the wavelength of the infrared communication wave becomes high, and infrared absorbing particles having a light blue color and high weather resistance (heat resistance, heat and humidity resistance) are obtained.

The first heat treatment step may be implemented in one step, or a plurality of steps in which the environment and temperature are changed during the heat treatment may be employed. For example, in the first step, heat treatment can be performed at 400° C. to 850° C. under a mixed gas atmosphere of an inert gas and an oxygen source gas, and at 400° C. or higher under an inert gas atmosphere in the second step. Heat treatment below 850°C. In this manner, by performing the first heat treatment step in a plurality of steps, it is possible to obtain infrared-absorbing particles having a particularly excellent infrared-absorbing function. (2-2) Second heat treatment process The second heat treatment step (non-oxidizing gas heat treatment step) is a step of performing heat treatment in an atmosphere containing one or more second gases selected from reducing gases and inert gases.

By performing the second heat treatment step, oxygen pores can be formed in the infrared absorbing particles.

The atmosphere during the heat treatment in the second heat treatment step may be an inert gas alone, a reducing gas alone, or a mixed gas of an inert gas and a reducing gas as already described.

The inert gas is not particularly limited, and one or more gases selected from nitrogen, argon, helium, and the like can be used.

The reducing gas is not particularly limited, and for example, one or more gases selected from hydrogen, alcohol, and the like can be used.

When using a mixed gas of an inert gas and a reducing gas as the second gas, the concentration of the reducing gas in the inert gas may be appropriately selected according to the heat treatment temperature, the amount of raw material powder to be heat treated, etc. special limited. The concentration of the reducing gas in the second gas is, for example, preferably 20% by volume or less, more preferably 10% by volume or less, and even more preferably 7% by volume or less.

This is because by setting the concentration of the reducing gas in the second gas to 20% by volume or less, generation of WO ₂ , W, etc. that do not have an infrared shielding function due to rapid reduction can be avoided.

When a mixed gas is used as the second gas, the concentration of the reducing gas in the second gas, that is, the lower limit of the content ratio is not particularly limited, but the content ratio of the reducing gas in the second gas is preferably more than 1% by volume. . This is because, when the content ratio of the reducing gas in the second gas exceeds 1% by volume, oxygen pores can be generated more reliably.

The temperature during the heat treatment in the second heat treatment step is not particularly limited as long as it is appropriately selected according to the environment, the amount of raw material powder to be heat-treated, and the like. When the environment is an inert gas alone, it is preferably 400°C to 1200°C, more preferably 500°C to 1000°C, and even more preferably 500°C to 900°C from the viewpoint of crystallinity and coloring power. Even when the second gas contains a reducing gas, the second heat treatment temperature is not particularly limited, and for example, the same temperature range as when the second gas is an inert gas alone can be set as an appropriate range.

The second heat treatment step may be implemented in one step, or a plurality of steps in which the environment and temperature are changed during the heat treatment may be employed. For example, in the first step, heat treatment can be performed at 400°C to 850°C under a mixed gas atmosphere of an inert gas and a reducing gas, and at 800°C or higher under an inert gas atmosphere in the second step. Heat treatment below 1000°C. In this manner, by performing the second heat treatment step in a plurality of steps, it is possible to obtain infrared-absorbing particles having a particularly excellent infrared-absorbing function.

The heat treatment time in the second heat treatment step is also not particularly limited, as long as it is appropriately selected according to the heat treatment temperature, environment, and the amount of raw material powder to be heat treated, for example, it may be 5 minutes to 7 hours.

By performing the heat treatment steps up to the above, the infrared absorbing particles described above can be obtained. In addition, the method for producing infrared-absorbing particles according to the present embodiment may include a pulverization step of pulverizing the infrared-absorbing particles, a sieving step, and the like in order to form a desired particle size as necessary. (3) Modification process As already described, the surface of the infrared-absorbing particles may be modified with a compound containing one or more atoms selected from Si, Ti, Zr, and Al. Therefore, the method for producing infrared-absorbing particles can further include, for example, a modification step of modifying the infrared-absorbing particles with a compound containing one or more atoms selected from Si, Ti, Zr, and Al.

In the modification step, specific conditions for modifying the infrared absorbing particles are not particularly limited. For example, a modification step of adding an alkoxide containing one or more metals selected from the above-mentioned metal group to the modified infrared-absorbing particles to form a film on the surface of the infrared-absorbing particles may also be included. 3. Infrared Absorbing Particle Dispersion The infrared-absorbing particle dispersion of the present embodiment can contain a liquid medium and the infrared-absorbing particles already described. Specifically, for example, as schematically shown in FIG. 1 , the infrared-absorbing particle dispersion 10 can include the liquid medium 12 and the infrared-absorbing particles 11 already described. Preferably, the infrared absorbing particles 11 described above are disposed in the liquid medium 12 and dispersed in the liquid medium 12 . In addition, FIG. 1 is a schematic diagram, and the infrared-absorbing particle dispersion liquid of this embodiment is not limited to this form. For example, in FIG. 1 , the infrared-absorbing particles 11 are described as spherical particles, but the shape of the infrared-absorbing particles 11 is not limited to such a form, and can have any shape. As already described, the infrared absorbing particles 11 can also have a coating on the surface, for example. The infrared-absorbing particle dispersion 10 may contain other additives as necessary in addition to the infrared-absorbing particles 11 and the liquid medium 12 . (1) About the ingredients to include As described above, the infrared-absorbing particle dispersion of the present embodiment can contain a liquid medium and the infrared-absorbing particles described above. Since the infrared absorbing particles have already been described, description thereof will be omitted. Hereinafter, it will be described that the liquid medium and the infrared absorbing particle dispersion liquid may contain a dispersant and the like as necessary. (1-1) About liquid medium The liquid medium is not particularly limited, and various liquid mediums can be used, for example, one selected from the liquid medium material group consisting of water, organic solvents, fats, liquid resins, and liquid plasticizers for plastics can be used, Or a mixture of two or more selected from the liquid medium material group.

As the organic solvent, various organic solvents such as alcohol-based, ketone-based, ester-based, amide-based, hydrocarbon-based, glycol-based, and the like can be selected. Specifically, methanol, ethanol, 1-propanol, isopropanol (isopropyl alcohol), butanol, pentanol, benzyl alcohol, diacetone alcohol, 1-methoxy-2-propanol, etc. Alcohol-based solvents; ketone-based solvents such as dimethyl ketone, acetone, methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, cyclohexanone, and isophorone; 3-methyl-methoxy Ester-based solvents such as propionate and butyl acetate; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol isopropyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, Diol inducers such as propylene glycol methyl ether acetate and propylene glycol ethyl ether acetate; formamide, N-methylformamide, dimethylformamide, dimethylacetamide, N-formamide Amides such as base-2-pyrrolidone; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as vinyl chloride and chlorobenzene, etc. Among these, organic solvents with low polarity are preferred, and isopropyl alcohol, ethanol, 1-methoxy-2-propanol, dimethyl ketone, methyl ethyl ketone, methyl isobutyl alcohol are more preferred. Ketones, toluene, propylene glycol monomethyl ether acetate, n-butyl acetate, etc. These solvents can be used alone or in combination of two or more. In addition, acid and alkali may be added to adjust pH as needed.

As the fat, for example, dry oils such as linseed oil, sunflower oil, and tung oil, semi-dry oils such as sesame oil, cottonseed oil, rapeseed oil, soybean oil, and rice bran oil, olive oil, coconut oil, palm oil, dehydrated castor oil, etc., can be used. Non-drying oils such as sesame oil, fatty acid monoesters, ethers, ISOPER (registered trademark) E, EXXSOL (registered trademark) Hexane, Heptane, E, D30, D40, D60, D80, One or more of petroleum-based solvents such as D95, D110, and D130 (above, manufactured by EXXON MOBIL).

As the liquid resin, it is possible to use a liquid resin obtained by dissolving monomers, oligomers, thermoplastic resins, etc., such as methyl methacrylate and styrene, which are cured by polymerization or the like, in a liquid medium.

Examples of liquid plasticizers for plastics include plasticizers that are compounds of monohydric alcohols and organic acid esters, ester-based plasticizers such as polyhydric alcohol organic acid ester compounds, and organic phosphoric acid-based plasticizers. Phosphate-based plasticizers such as plasticizers are preferred examples. Among them, triethylene glycol di-2-ethylhexanoate, triethylene glycol di-2-ethylbutyrate, and tetraethylene glycol di-2-ethylhexanoate are more preferable because of their low hydrolyzability. (1-2) Dispersant, coupling agent, surfactant The infrared-absorbing particle dispersion liquid of the present embodiment may also contain one or more selected from the group consisting of a dispersant, a coupling agent, and a surfactant as needed.

The dispersant, coupling agent, and surfactant can be selected according to the application, and those having an amine-containing group, a hydroxyl group, a carboxyl group, or an epoxy group as a functional group can be suitably used.

Even when the above-mentioned functional group is adsorbed on the surface of the infrared-absorbing particles to prevent aggregation of the infrared-absorbing particles, for example, when it is formed into an infrared-absorbing film or the like, it has the effect of particularly uniformly dispersing the infrared-absorbing particles in the infrared-absorbing film.

The infrared-absorbing particle dispersion liquid of this embodiment can contain a dispersant. Such a dispersant also includes a coupling agent and a surfactant that function as a dispersant. As a dispersant that can be suitably used, one or more selected from phosphoric acid ester compounds, polymeric dispersants, silane-based coupling agents, titanate-based coupling agents, aluminum-based coupling agents, etc., can be mentioned, and Not limited to this.

Examples of polymer dispersants include acrylic polymer dispersants, urethane polymer dispersants, acrylic-block copolymer polymer dispersants, polyether dispersants, polyester-based One or more types of polymer dispersants and the like.

The amount of the dispersant added is desirably in the range of 10 parts by mass to 1000 parts by mass, more preferably in the range of 20 parts by mass to 200 parts by mass, relative to 100 parts by mass of the infrared absorbing particles. When the added amount of the dispersant is within the above range, the infrared absorbing particles do not cause aggregation in the liquid medium, and in particular, the dispersion stability can be maintained. (2) About the method of adding infrared absorbing particles to the liquid medium The method of adding the infrared-absorbing particles to the liquid medium is not particularly limited, but a method capable of uniformly dispersing the infrared-absorbing particles in the liquid medium is preferable.

For example, one or more types selected from bead mills, ball mills, sand mills, paint shakers, ultrasonic homogenizers and the like can be mentioned.

By the dispersion treatment using these dispersing means, the dispersion of the infrared absorbing particles into the liquid medium is carried out simultaneously with the micronization due to the collision of the infrared absorbing particles, etc., and the infrared absorbing particles can be further micronized and dispersion. That is, when performing dispersion treatment, pulverization and dispersion treatment can be performed.

The content of the infrared-absorbing particles in the above-mentioned infrared-absorbing particle dispersion is not particularly limited, but the infrared-absorbing particle dispersion of the present embodiment preferably contains 0.001% by mass to 80.0% by mass of infrared particles. If it is 0.001% by mass or more, it can be suitably used in the manufacture of coating layers, plastic moldings, etc., which are one type of infrared-absorbing particle dispersion containing infrared-absorbing particles, and if it is 80.0% by mass or less, it is suitable for industrial production. easy. In the infrared-absorbing particle dispersion, the content of the infrared-absorbing particles is more preferably from 0.01% by mass to 80.0% by mass, and still more preferably from 1% by mass to 35% by mass.

In addition, when the visible light transmittance of the infrared-absorbing particle dispersion is 80%, the concentration of the infrared-absorbing particles in the infrared-absorbing particle dispersion is preferably 0.05% by mass or more and 0.20% by mass or less.

When the visible light transmittance of the infrared-absorbing particle dispersion is 80%, the concentration of the infrared-absorbing particles in the infrared-absorbing particle dispersion is 0.05 mass % to 0.20 mass %, sufficient near-infrared absorption characteristics can be obtained.

In the infrared-absorbing particle dispersion liquid of the present embodiment, the color tone when calculating the light absorption only by the infrared-absorbing particles with the light transmittance of the liquid medium as a base line is preferably in the L ^* a ^* b ^* colorimetric system b ^* >0. Satisfying the above range means light blue infrared absorbing particles.

The light transmittance of the infrared-absorbing particle dispersion can be measured as a function of wavelength by putting the infrared-absorbing particle dispersion of the present embodiment into an appropriate transparent container and using a spectrophotometer. (3) Regarding the average dispersed particle size The characteristics of the infrared-absorbing particle dispersion of the present embodiment can be confirmed by measuring the dispersion state of the infrared-absorbing particles when the infrared-absorbing particles are dispersed in a liquid medium. For example, the state of the infrared-absorbing particles in the dispersion can be confirmed by taking a sample of the infrared-absorbing particle dispersion according to the embodiment and measuring it with various commercially available particle size distribution meters. As a particle size distribution meter, it can measure using DLS-8000 by Otsuka Electronics Co., Ltd. whose principle is a dynamic light scattering method, for example.

The particle size of the infrared-absorbing particles in the infrared-absorbing particle dispersion of the present embodiment can be selected according to the purpose of use of the infrared-absorbing dispersion and the like, and is not particularly limited.

In the infrared-absorbing particle dispersion of the present embodiment, the average dispersed particle diameter of the infrared-absorbing particles is preferably, for example, 1 nm to 800 nm, more preferably 1 nm to 400 nm. This is because when the average dispersed particle size is 800 nm or less, the strong infrared absorption ability of the infrared absorbing particles can be exhibited, and when the average dispersed particle size is 1 nm or more, industrial production is easy.

In particular, when the average dispersed particle size is 400 nm or less, the infrared shielding film and the molded article (plate, sheet) can be prevented from becoming grayish in which the transmittance decreases monotonously. In addition, by setting the average dispersed particle size to 400 nm or less, when the infrared absorbing particle dispersion liquid is used to form an infrared absorbing particle dispersion or the like, fogging can be particularly suppressed and visible light transmittance can be improved.

When the infrared-absorbing particle dispersion is used in an application that particularly requires transparency in the visible region, the infrared-absorbing particles in the infrared-absorbing particle dispersion preferably have an average dispersed particle diameter of 40 nm or less. Here, the average dispersed particle size is the 50% volume cumulative particle size measured using DLS-8000 manufactured by Otsuka Electronics Co., Ltd. based on the principle of the dynamic light scattering method. This is because if the infrared-absorbing particles have an average dispersed particle diameter of less than 40 nm, the scattering of light by Mie scattering and Rayleigh scattering of the infrared-absorbing particles can be sufficiently suppressed, and the visibility of light in the visible light region can be maintained. high while efficiently maintaining transparency. When used in applications requiring transparency, such as windshields for automobiles, the average dispersed particle size of the infrared absorbing particles is more preferably 30 nm or less, and still more preferably 25 nm or less, in order to further suppress scattering. 4. Infrared absorbing particle dispersion Next, the infrared-absorbing particle dispersion of the present embodiment will be described.

The infrared-absorbing particle dispersion of the present embodiment can contain a solid medium and the infrared-absorbing particles already described arranged in the solid medium. Specifically, for example, as schematically shown in FIG. 2 , the infrared-absorbing particle dispersion 20 can have a solid medium 22 and the infrared-absorbing particles 21 already described, and the infrared-absorbing particles 21 can be arranged in the solid medium 22 . The infrared absorbing particles 21 are preferably dispersed in the solid medium 22 . In addition, FIG. 2 is a schematic diagram, and the infrared-absorbing particle dispersion of this embodiment is not limited to such a form. For example, in FIG. 2 , the infrared-absorbing particles 21 are described as spherical particles, but the shape of the infrared-absorbing particles 21 is not limited to such a form, and can have any shape. The infrared absorbing particles 21 may have a coating on the surface, for example. In addition to the infrared absorbing particles 21 and the solid medium 22, the infrared absorbing particle dispersion 20 can also contain other additives as necessary. (1) About the ingredients to include As described above, the infrared-absorbing particle dispersion of the present embodiment can contain a solid medium and the infrared-absorbing particles already described. The infrared absorbing particles have already been described, and the description thereof will be omitted. Hereinafter, the solid medium and the components that can be contained in the infrared absorbing particle dispersion as needed will be described. (1-1) Solid medium First, a solid medium which is a solid medium will be described.

The solid medium is not particularly limited as long as it can be cured in a state where infrared absorbing particles are dispersed. Examples thereof include inorganic binders obtained by hydrolyzing metal alkoxides, and organic binders such as resins.

In particular, the solid medium preferably contains a thermoplastic resin or a UV curable resin (ultraviolet curable resin). In addition, in the infrared-absorbing particle dispersion according to the present embodiment, if it is liquid in the manufacturing process and finally solid, it can be a solid medium.

When the solid medium contains a thermoplastic resin, the thermoplastic resin is not particularly limited, and can be arbitrarily selected according to required transmittance, strength, and the like. As thermoplastic resins, for example, those selected from polyethylene terephthalate resins, polycarbonate resins, acrylic resins, styrene resins, polyamide resins, polyethylene resins, vinyl chloride resins, olefin resins, One kind of resin in the resin group consisting of epoxy resin, polyimide resin, fluororesin, ethylene-vinyl acetate copolymer, and polyvinyl acetal resin, or two or more kinds selected from the above resin group Either a mixture of resins or a copolymer of two or more resins selected from the above resin group.

On the other hand, when the solid medium contains a UV curable resin, the UV curable resin is not particularly limited, and for example, an acrylic UV curable resin can be suitably used. (1-2) Regarding other ingredients In the method for producing the infrared-absorbing particle dispersion, the infrared-absorbing particle dispersion may also contain a dispersant, a plasticizer, and the like as described later. (2) Regarding the content of infrared absorbing particles The content of the infrared-absorbing particles dispersed in the infrared-absorbing particle dispersion is not particularly limited, and can be arbitrarily selected according to the application or the like. The content of the infrared absorbing particles in the infrared absorbing particle dispersion is, for example, preferably from 0.001% by mass to 80.0% by mass, more preferably from 0.01% by mass to 70.0% by mass.

When the content of the infrared-absorbing particles in the infrared-absorbing particle dispersion is 0.001% by mass or more, the thickness of the dispersion for obtaining the necessary infrared-absorbing effect of the infrared-absorbing particle dispersion can be suppressed. Therefore, it is because it can be used for many purposes, and transportation is also easy.

In addition, this is because by making the content of the infrared absorbing particles 80.0% by mass or less, the content ratio of the solid medium in the infrared absorbing particle dispersion can be ensured, and the strength can be increased.

The content of the infrared absorbing particles per unit projected area contained in the infrared absorbing particle dispersion is preferably 0.04 g/m ² or more and 10.0 g/m ² or less. In addition, "content per unit projected area" refers to the weight (g) of infrared absorbing particles contained in the thickness direction per unit area (m ² ) through which light passes in the infrared absorbing particle dispersion of the present embodiment.

By setting the content per unit projected area of the infrared-absorbing particle dispersion within the above range, it is possible to keep the infrared-absorbing effect high while maintaining the strength of the infrared-absorbing particle dispersion.

In the infrared-absorbing particle dispersion of the present embodiment, the color tone when calculating light absorption only by the infrared-absorbing particles is preferably b ^* >0 in the L ^* a ^* b ^* color system. Satisfying the above-mentioned range means that it is a light blue infrared-absorbing particle. The same applies to the infrared-absorbing interlayer transparent substrate and the infrared-absorbing transparent substrate to be described later. (3) Shape of Infrared Absorbing Particle Dispersion The infrared absorbing particle dispersion can be molded into any shape according to the application, and the shape is not particularly limited.

The infrared absorbing particle dispersion can have, for example, a sheet shape, a plate shape, or a film shape, and can be applied to various uses.

(4) About the production method of the infrared absorbing particle dispersion Here, a method for producing the infrared-absorbing particle dispersion of the present embodiment will be described.

The infrared-absorbing particle dispersion can also be produced, for example, by mixing the above-mentioned solid medium with the infrared-absorbing particles described above, molding it into a desired shape, and then curing it.

In addition, the infrared-absorbing particle dispersion can also be produced using, for example, the infrared-absorbing dispersion liquid already described. In this case, the infrared-absorbing particle dispersion powder, the plasticizer dispersion liquid, and the masterbatch described below can first be produced, and then the infrared-absorbing particle dispersion powder and the like can be used to produce an infrared-absorbing particle dispersion. It will be specifically described below.

First, a mixing step of mixing the already described infrared absorbing particle dispersion with a thermoplastic resin or a plasticizer can be carried out. Next, a drying step of removing the solvent component (liquid medium component) originating from the infrared absorbing particle dispersion can be performed.

By removing the solvent component, it is possible to obtain an infrared absorbing particle dispersion powder (hereinafter, It may be simply referred to as "dispersion powder"), and a dispersion liquid in which infrared-absorbing particles are dispersed at a high concentration in a plasticizer (hereinafter, may be simply referred to as "plasticizer dispersion liquid").

The method for removing the solvent component from the mixture of the infrared-absorbing particle dispersion and thermoplastic resin is not particularly limited. For example, a method of drying the mixture of infrared-absorbing particle dispersion and thermoplastic resin under reduced pressure is preferably used. Specifically, the mixture of the infrared absorbing particle dispersion and the thermoplastic resin is dried under reduced pressure while being stirred, and separated into a dispersed powder or a plasticizer dispersion and a solvent component. As an apparatus used for this reduced-pressure drying, the drying machine of a vacuum stirring type is mentioned, As long as it is an apparatus which has the above-mentioned function, it will not specifically limit. In addition, the pressure value at the time of depressurization in a drying process is not specifically limited, It can select arbitrarily.

By using a reduced-pressure drying method when removing the solvent component, the removal efficiency of the solvent from the mixture of the infrared-absorbing particle dispersion liquid and the thermoplastic resin or the like can be improved. In addition, in the case of using the reduced-pressure drying method, since the infrared-absorbing particle dispersion powder and the plasticizer dispersion liquid are not exposed to high temperature for a long time, aggregation of the infrared-absorbing particles dispersed in the dispersion powder or plasticizer dispersion liquid does not occur. , is preferred. Furthermore, the productivity of the infrared-absorbing particle dispersion powder and the plasticizer dispersion liquid is also improved, and the evaporated solvent is also easy to recover, which is preferable from the viewpoint of the environment.

In addition, as described above, a masterbatch can also be used when producing the infrared-absorbing particle dispersion.

The masterbatch can be manufactured, for example, by dispersing an infrared-absorbing particle dispersion liquid or an infrared-absorbing particle dispersion powder in a resin, and granulating the resin.

As another production method of the masterbatch, first, the infrared-absorbing particle dispersion liquid, the infrared-absorbing particle dispersion powder, the powder or granule of the thermoplastic resin, and other additives as necessary are uniformly mixed. Then, the mixture can be produced by kneading the mixture with a vented single-screw or twin-screw extruder, and processing it into pellets by cutting a generally melt-extruded strand. In this case, examples of the shape thereof include columnar and prismatic masterbatches. In addition, a so-called thermal cutting method in which a molten extrudate is directly cut can also be employed. In this case, a shape close to a spherical shape is generally adopted.

Through the above steps, the infrared absorbing particle dispersion powder, the plasticizer dispersion liquid, and the masterbatch can be produced.

Furthermore, the infrared-absorbing particle dispersion of the present embodiment can be manufactured by uniformly mixing the infrared-absorbing particle dispersion powder, the plasticizer dispersion, or the masterbatch in a solid medium, and molding it into a desired shape. At this time, as the solid medium, as already described, organic binders such as inorganic binders and resins can be used. As the binder, thermoplastic resins and UV curable resins can be used particularly preferably. Thermoplastic resins and UV curable resins that can be particularly suitably used have already been described, and descriptions thereof are omitted here.

In the case of using a thermoplastic resin as a solid medium, the infrared absorbing particle dispersion powder, plasticizer dispersion or masterbatch, thermoplastic resin, and other additives depending on the desired plasticizer can be kneaded first. Furthermore, the kneaded product can be produced by various molding methods such as extrusion molding, injection molding, calender roll method, extrusion method, casting method, and inflation method, for example, into flat or curved shapes. Dispersion of infrared absorbing particles in the form of flakes.

In addition, when the solid medium is used as an intermediate layer in which an infrared-absorbing particle dispersion using a thermoplastic resin is arranged, for example, between transparent substrates, etc., the thermoplastic resin contained in the infrared-absorbing particle dispersion is insufficient. In the case of having flexibility and adhesiveness to a transparent substrate or the like, a plasticizer can be added when producing the infrared absorbing particle dispersion. Specifically, for example, when the thermoplastic resin is polyvinyl acetal resin, it is preferable to further add a plasticizer.

The plasticizer to be added is not particularly limited, and can be used as long as it functions as a plasticizer for the thermoplastic resin used. For example, when a polyvinyl acetal resin is used as a thermoplastic resin, as a plasticizer, a plasticizer that is a compound of a monohydric alcohol and an organic acid ester, or an ester-based plasticizer such as a polyhydric alcohol organic acid ester compound can be preferably used. Phosphoric acid-based plasticizers such as organic phosphoric acid-based plasticizers, etc.

Since the plasticizer is preferably liquid at room temperature, it is preferably an ester compound synthesized from a polyhydric alcohol and a fatty acid.

Also, as already described, the infrared-absorbing particle dispersion of the present embodiment can have any shape, for example, can have a sheet shape, a plate shape, or a film shape. 5. Infrared absorption interlayer transparent substrate Next, a configuration example of the infrared-absorbing interlayer transparent substrate of the present embodiment will be described.

The infrared-absorbing interlayer transparent substrate of the present embodiment can have a plurality of transparent substrates and the infrared-absorbing particle dispersion of the present embodiment. Furthermore, the infrared absorbing particle dispersion can have a laminated structure arranged between a plurality of transparent substrates.

Specifically, as shown in FIG. 3 which is a schematic cross-sectional view along the stacking direction of the transparent substrate and the infrared-absorbing particle dispersion, the infrared-absorbing interlayer transparent substrate 30 can have a plurality of transparent substrates 311, 312 and infrared rays. Absorb particle dispersion 32 . Furthermore, the infrared absorbing particle dispersion 32 can be arranged between the plurality of transparent substrates 311 and 312 . In FIG. 3, although the example which has two transparent base materials 311 and 312 was shown, it is not limited to this form.

The infrared-absorbing interlayer transparent base material of the present embodiment can have a structure in which the infrared-absorbing particle dispersion as an intermediate layer is sandwiched from both sides by a transparent base material (transparent substrate).

The transparent substrate is not particularly limited, and can be arbitrarily selected in consideration of visible light transmittance and the like. For example, as the transparent substrate, one or more selected from plate glass, plate-like plastic, plate-like plastic, film-like plastic, and the like can be used. In addition, the transparent substrate is preferably transparent in the visible light region.

In the case of using a plastic transparent substrate, the material of the plastic is not particularly limited and can be selected according to the application. Polycarbonate resin, acrylic resin, polyethylene terephthalate resin, polyamide resin, etc. can be used. Resin, vinyl chloride resin, olefin resin, epoxy resin, polyimide resin, fluororesin, etc.

In addition, the infrared-absorbing interlayer transparent base material of the present embodiment can use two or more transparent base materials, and in the case of using two or more transparent base materials, for example, a combination of different material to form a transparent substrate. In addition, the thicknesses of the transparent base materials to be constituted do not need to be the same, and transparent base materials having different thicknesses may be used in combination.

The infrared-absorbing interlayer transparent substrate of the present embodiment can use the infrared-absorbing particle dispersion already described as an intermediate layer. The infrared absorbing particle dispersion has already been described, and the description is omitted here.

The infrared-absorbing particle dispersion used in the infrared-absorbing interlayer transparent substrate of the present embodiment is not particularly limited, and one molded into a sheet shape, a plate shape, or a film shape can be preferably used.

Furthermore, the infrared-absorbing interlayer transparent substrate according to the present embodiment can be produced by bonding and integrating a plurality of opposing transparent substrates sandwiching the infrared-absorbing particle dispersion molded into a sheet shape or the like.

In addition, when the infrared-absorbing interlayer transparent substrate has three or more transparent substrates, there are two or more locations between the transparent substrates, and it is not necessary to arrange the infrared-absorbing particle dispersion between all the transparent substrates. It is sufficient to arrange the infrared absorbing particle dispersion at least one place. 6. Infrared absorbing transparent substrate The infrared-absorbing transparent substrate of the present embodiment can have a transparent substrate and an infrared-absorbing layer arranged on at least one surface of the transparent substrate. Furthermore, it is possible to make the infrared absorbing layer a dispersion of infrared absorbing particles as already described. Specifically, as shown in FIG. 4 , which is a schematic cross-sectional view along the stacking direction of the transparent substrate and the infrared-absorbing layer, the infrared-absorbing transparent substrate 40 can have a transparent substrate 41 and an infrared-absorbing layer 42 . The infrared absorbing layer 42 can be arranged on at least one surface 41A of the transparent substrate 41 .

The method for producing the infrared-absorbing transparent substrate is not particularly limited. For example, the above infrared absorbing particle dispersion can be used to form a coating layer as an infrared absorbing layer containing infrared absorbing particles on a transparent substrate (transparent substrate) selected from a film substrate and a glass substrate. Through such operations, an infrared-absorbing film or infrared-absorbing glass as an infrared-absorbing transparent substrate can be produced.

The coating layer can be produced using a coating liquid in which, for example, the dispersion liquid of infrared absorbing particles described above is mixed with a plastic or a monomer.

For example, an infrared absorbing film can be produced as follows.

A dielectric resin that becomes a solid medium after curing is added to the above-mentioned infrared-absorbing particle dispersion liquid to obtain a coating liquid. After the coating liquid is applied to the surface of the film substrate, the liquid medium containing the coating liquid is evaporated. Then, by curing the dielectric resin by a method corresponding to the dielectric resin used, a coating layer (coating film) in which the infrared-absorbing particles are dispersed in a solid medium can be formed to form an infrared-absorbing film.

In addition, by using a glass substrate as the transparent substrate, infrared-absorbing glass can also be produced in the same manner.

The dielectric resin of the coating layer can be selected from, for example, UV curable resins, thermosetting resins, electron beam curable resins, room temperature curable resins, thermoplastic resins, etc. according to purposes. Specific examples of the medium resin include polyethylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl alcohol resin, polystyrene resin, polypropylene resin, ethylene vinyl acetate copolymer , polyester resin, polyethylene terephthalate resin, fluororesin, polycarbonate resin, acrylic resin, polyvinyl butyral resin, etc.

These medium resins may be used alone or in combination. Among the dielectric resins for the coating layer, it is most particularly preferable to use a UV curable resin binder from the viewpoint of productivity, device cost, and the like.

In addition, a binder using a metal alkoxide can also be used. As the metal alkoxide, alkoxides of Si, Ti, Al, Zr, etc. are representative. The binder using these metal alkoxides is hydrolyzed and polycondensed by heating or the like, so that the solid medium can form a coating layer made of an oxide film.

As the material of the film substrate, polyester resin, acrylic resin, urethane resin, polycarbonate resin, polyethylene resin, ethylene vinyl acetate copolymer, vinyl chloride resin, fluororesin, etc. can be used according to various purposes. Wait. As the film substrate of the infrared absorbing film, a polyester film is preferred, and a polyethylene terephthalate (PET) film is most preferred. The film substrate refers to a plastic substrate that is a synthetic resin, and its thickness and shape are not limited.

In addition, in order to realize the ease of adhesion of the coating layer to the film base material, the surface of the film base material is preferably surface-treated. In addition, in order to improve the adhesion between the glass substrate or the film substrate and the coating layer, it is also preferable to form an intermediate layer on the glass substrate or the film substrate, and to form the coating layer on the intermediate layer. The composition of the intermediate layer is not particularly limited, and can be composed of, for example, a polymer film, a metal layer, an inorganic layer (for example, an inorganic oxide layer such as silicon dioxide, titanium dioxide, or zirconia), an organic/inorganic composite layer, and the like.

In order to provide a coating layer on a film base material or a glass base material, the method of coating a coating liquid containing a dispersion liquid containing infrared absorbing particles and the like may be such that the dispersion liquid containing infrared absorbing particles etc. can be uniformly applied to the surface of the substrate The method of applying the liquid is not particularly limited. For example, a bar coating method, a gravure coating method, a spray coating method, a dip coating method, etc. are mentioned.

For example, in the case of bar coating using a UV curable resin, an infrared-absorbing transparent substrate can be produced as follows.

It is possible to adjust the liquid concentration in such a way as to have moderate leveling. Using a coating liquid with additives added appropriately, the wire rod with the rod number selected according to the thickness of the coating layer and the content of infrared-absorbing particles, etc., is applied to the film. A coating film is formed on a substrate or a glass substrate. Furthermore, after the liquid medium contained in the coating liquid is removed by drying, the solid medium can be cured by irradiating with ultraviolet rays, whereby a coating layer can be formed on a film substrate or a glass substrate. At this time, the drying conditions of the coating film vary depending on the components, the type of the liquid medium, and the use ratio, but are usually at a temperature of 60° C. to 140° C. for 20 seconds to 10 minutes. The irradiation of ultraviolet rays is not particularly limited, and for example, a UV exposure machine such as an ultra-high pressure mercury lamp can be suitably used.

In addition, the adhesion between the transparent substrate and the coating layer, the smoothness of the coating film during coating, the drying property of the organic solvent, and the like can also be adjusted in the pre-process or post-process of the formation of the coating layer. As a pre-process, there are, for example, a surface treatment process of a transparent base material, a pre-baking (pre-heating of the base material) process, etc., and as a post-process, a post-baking (post-heating of the base material) process, etc., can be appropriately selected. . Preferably, the heating temperature in the pre-baking step and the post-baking step is 80° C. to 200° C., and the heating time is 30 seconds to 240 seconds.

The thickness of the coating layer on the film substrate or the glass substrate is not particularly limited, but is practically preferably 10 μm or less, more preferably 6 μm or less. This is because if the thickness of the coating layer is 10 μm or less, it will exhibit sufficient pencil hardness and have rubbing resistance. In addition, when the volatilization of the liquid medium in the coating layer and the solidification of the solid medium can prevent the film substrate from warpage etc.

The content of the infrared absorbing particles in the coating layer is not particularly limited, but the content per unit projected area of the coating layer is preferably 0.1 g/m ² or more and 10.0 g/m ² or less. This is because, when the content per unit projected area is 0.1 g/m ² or more, the infrared absorbing particles can exhibit particularly high infrared absorbing properties.

In addition, this is because if the content per unit projected area is 10.0 g/m ² or less, the visible light transmittance of the infrared-absorbing transparent substrate can be sufficiently maintained.

In addition, in order to further impart an ultraviolet absorbing function to the infrared absorbing film and infrared absorbing glass as the infrared absorbing transparent substrate of the present embodiment, particles of inorganic titanium oxide, zinc oxide, cerium oxide, etc., organic diphenyl At least one or more of ketone, benzotriazole, and the like are added to the coating layer and the like. 7. About physical properties Infrared-absorbing particle dispersion, infrared-absorbing particle dispersion, infrared-absorbing interlayer transparent substrate, infrared-absorbing transparent substrate (collectively described as "infrared-absorbing particle dispersion, etc."), optical The characteristics can be selected according to the use and the like, and are not particularly limited.

The light transmittance of the infrared absorbing particle dispersion or the like at a wavelength of 850 nm is preferably 30% or more, more preferably 35% or more. This is because the transmittance of signals of mobile phones and various sensors can be increased by making the transmittance of light with a wavelength of 850 nm 30% or more.

The visible light transmittance of the infrared absorbing particle dispersion and the like is preferably 70% or more. This is because by making the visible light transmittance 70% or more, it shows that the transparency with respect to visible light is excellent, and even when it is used for the window glass of a passenger car, etc., visibility can fully be improved.

The solar transmittance of the infrared absorbing particle dispersion and the like is preferably 65% or less, more preferably 60% or less. This is because the intrusion of infrared rays into a room or the like can be sufficiently suppressed by setting the sunlight transmittance to 65% or less.

Furthermore, the infrared absorbing particle dispersion and the like preferably have a light transmittance of 25% or less at a wavelength of 1550 nm from the viewpoint of effectively suppressing the burning sensation.

The haze value of the infrared absorbing particle dispersion or the like is preferably 2% or less, more preferably 1% or less. By setting the haze value to 2% or less, fogging is suppressed, and visibility when used for window glass or the like can be improved.

The infrared-absorbing particles, infrared-absorbing particle dispersion, infrared-absorbing particle dispersion, infrared-absorbing interlayer transparent substrate, and infrared-absorbing transparent substrate of the present embodiment can be used in various applications, and the applications are not particularly limited. For example, it can be used for single-plate glass, laminated glass, plastic, fiber, and other infrared-absorbing materials used in windows, telephone boxes, display windows, lighting lamps, and transparent cases of vehicles, buildings, offices, and general houses, etc. Function as necessary wide field. Example

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following Examples.

First, the evaluation method of the samples in the following Examples and Comparative Examples will be described. (1) Chemical analysis The chemical analysis of the composite tungsten oxide particles contained in the obtained infrared absorbing particles was carried out by atomic absorption analysis (AAS) for Cs and by ICP emission spectroscopic analysis (ICP-OES) for W. Oxygen is a method in which a sample is melted in He gas with a light element analyzer (LECO company type: ON-836), and CO gas generated by the reaction with carbon in the analysis crucible is quantified by IR absorption spectroscopy. to analyze. (2) Crystal structure, lattice constant The crystal structure and lattice constant of the composite tungsten oxide particles contained in the infrared absorbing particles obtained in the following examples and comparative examples were measured and calculated.

First, the X-ray diffraction pattern of the infrared-absorbing particles was obtained by the powder X-ray diffraction method (θ-2θ method) using a powder X-ray diffraction device (X'Pert-PRO/MPD manufactured by PANalytical, Spectris Co., Ltd.). To measure. The crystal structure of the composite tungsten oxide particles included in the particles was specified from the obtained X-ray diffraction pattern, and the lattice constant was further calculated by Rietveld analysis. In addition, the Rietveld analysis adopts the external standard method. Rietveld analysis of the X-ray diffraction pattern of the Si standard powder (NIST640c) measured at the same time was first performed, and the zero offset value and half-width parameter obtained at this time were set as device parameters, and the target composite tungsten oxide particles were Rietveld Parsing Refinement. (3) Spectral transmittance and color system of infrared absorbing particle dispersion In the following examples and comparative examples, the transmittance of the infrared-absorbing particle dispersion liquid was used in a spectrophotometer unit (manufactured by GL Sciences Co., Ltd., model: S10-SQ-1, material: synthetic quartz, optical path length: 1 mm) The dispersion liquid was retained in the middle, and measured using a spectrophotometer U-4100 manufactured by Hitachi, Ltd.

In this measurement, the liquid medium of the dispersion (such as methyl isobutyl ketone, hereinafter abbreviated as MIBK.) is filled with the cell to measure the transmittance, and the base line for the transmittance measurement is obtained. As a result, in the spectral transmittance and visible light transmittance described below, the contribution of light reflection from the surface of the spectrophotometer cell and light absorption of the liquid medium is excluded, and only the light contribution from the infrared absorbing particles is calculated. absorb.

Visible light transmittance and sunlight transmittance are measured at intervals of 5 nm in the transmission light spectrum in the wavelength range of 200 nm to 2600 nm, and calculated in the wavelength range of 300 nm to 2100 nm based on JIS A 5759 (2016).

In addition, the colorimetric system used the L ^* a ^* b ^* colorimetric system (D65 light source/10 degree field of view) based on JIS Z 8701 (1999), and measured the values of L ^* , a ^* , and b ^* . (4) The spectral transmittance of the infrared-absorbing transparent substrate and the infrared-absorbing interlayer transparent substrate, and the transmittance of the color-based infrared-absorbing transparent substrate and the infrared-absorbing interlayer transparent substrate were also used with a spectrophotometer manufactured by Hitachi, Ltd. U-4100 to determine. In addition, the sunlight transmittance and the visible light transmittance were measured and calculated under the same conditions as in the case of the evaluation before and after the following heat resistance test and the like. For the infrared-absorbing interlayer transparent substrate, the light transmittance at a wavelength of 850 nm was measured.

In addition, the colorimetric system used the L ^* a ^* b ^* colorimetric system (D65 light source/10 degree field of view) based on JIS Z 8701 (1999), and measured the values of L ^* , a ^* , and b ^* .

In addition, for the infrared-absorbing transparent substrate before and after the heat resistance test and heat resistance test described later, the transmitted light spectrum is measured at intervals of 5 nm in the range of wavelength 200 nm to 2600 nm, based on JIS A 5759 (2016), at wavelength 300 nm or more In the range below 2100nm, the visible light transmittance and sunlight transmittance were calculated. Heat Resistance Test, Moisture Resistance Test For each test, a test body cut out from the infrared-absorbing transparent base material produced in each Example and Comparative Example was provided.

In addition, the infrared-absorbing interlayer transparent base material was similarly subjected to a heat resistance test and a heat and humidity resistance test, and the sunlight transmittance before and after the heat resistance test and the heat and humidity resistance test were calculated. With respect to the infrared-absorbing interlayer transparent base material, samples subjected to the spectral transmittance, heat resistance test, and heat-and-moisture test were produced in each of the Examples and Comparative Examples, and each evaluation was performed. (5) Evaluation of heat resistance The infrared-absorbing transparent substrate was held in the air at 120° C. for 125 hours, and changes in visible light transmittance and sunlight transmittance before and after exposure to the above environment were evaluated. When the amount of change in solar transmittance before and after exposure in the infrared-absorbing transparent substrate was 1.0% or less, the heat resistance was judged to be good, and when the amount of change exceeded 1.0%, the heat resistance was judged to be insufficient.

Heat resistance evaluation was also performed on the infrared-absorbing interlayer transparent base material under the same conditions. (6) Moisture and heat resistance evaluation The infrared-absorbing transparent substrate was kept in an environment of 85° C. and a humidity of 95% for 94 hours, and changes in visible light transmittance and sunlight transmittance before and after exposure to the above-mentioned environment were evaluated. When the amount of change in solar transmittance before and after exposure in the infrared-absorbing transparent substrate was less than 2.0%, it was judged that the moisture and heat resistance was good, and when the amount of change was 2.0% or more, it was judged that the moisture and heat resistance was insufficient.

For the infrared-absorbing interlayer transparent substrate, the heat and humidity resistance was evaluated under the same conditions.

Hereinafter, preparation conditions and the like of samples of Examples and Comparative Examples will be described. [Example 1] (1) Production of Infrared Absorbing Particles Each powder of tungstic acid (H ₂ WO ₄ ) and cesium carbonate (Cs ₂ CO ₃ ) was equal to Cs/W (molar ratio)=0.29/1.00. After proportional weighing, they were thoroughly mixed using a crushing machine to prepare mixed powder (mixing process).

The mixed powder was subjected to reduction treatment at a temperature of 570° C. for 1 hour under supply of 3 vol % H ₂ gas with N ₂ gas as carrier gas (second heat treatment step).

Then, under the supply of 1 vol% compressed air with _N2 gas as the carrier gas, it was fired at a temperature of 820° C. for 0.5 hour (the first heat treatment process, the first step), and further, in _N2 gas atmosphere, at 820 °C for 0.5 hours (1st heat treatment step, 2nd step).

Through the above operations, cesium tungsten alloy (bronze) having hexagonal crystals, that is, infrared absorbing particles formed of cesium tungsten oxide particles (hereinafter abbreviated as "powder A1") was obtained.

As a result of chemical analysis of powder A1, Cs/W (molar ratio)=0.29/1. The composition ratios of other components are shown in the column of the chemical analysis composition ratio in Table 1. In addition, Table 1 shows the crystal structure and lattice constant of cesium tungsten oxide particles which are composite tungsten oxide particles. (2) Infrared Absorbing Particle Dispersion Weigh 23.0% by mass of powder A1, and have an acrylic polymer dispersant having an amine-containing group as a functional group (acrylic dispersant with an amine value of 48 mgKOH/g and a decomposition temperature of 250° C.) 18.4% by mass, 58.6% by mass of MIBK which is a liquid medium. These were filled in a paint shaker containing 0.3mmφZrO ₂ beads, pulverized and dispersed for 4 hours to obtain an infrared absorbing particle dispersion (hereinafter referred to simply as "dispersion B1").

The obtained dispersion liquid B1 was suitably diluted with MIBK so that the visible light transmittance becomes 80%, it put into the cell for a spectrophotometer, and the spectral transmittance was measured. In addition, the concentration of the infrared-absorbing particles at this time is shown in Table 2 as the concentration of infrared-absorbing particles. The colorimetric system was measured from the transmitted light spectrum when the dilution rate was adjusted so that the visible light transmittance was 80%, and the transmission light spectrum was measured. Table 2 shows the solar transmittance and the evaluation results of the above-mentioned color system. (3) Infrared absorbing transparent substrate Infrared-absorbing glass and infrared-absorbing film were fabricated and evaluated by the following procedure. Infrared-absorbing glass and infrared-absorbing film are examples of infrared-absorbing transparent substrates, and the coating layer as an infrared-absorbing layer (infrared-absorbing particle layer) is an infrared-absorbing particle dispersion. (3-1) Manufacture of infrared absorbing glass 100% by mass of the obtained dispersion liquid B1 was mixed with 50% by mass of Aronix UV-3701 (hereinafter, referred to as UV-3701.) manufactured by Toagosei Co., Ltd. as an ultraviolet curable resin for a hard coat layer to prepare infrared absorbing particles Coating liquid (hereinafter referred to as "coating liquid C1"). The coating liquid C1 was coated on blue plate glass (HPE-50 manufactured by Teijin) having a thickness of 3 mm using a bar coater (No. 16) to form a coating film. In addition, the same glass was used when manufacturing infrared-absorbing glass in other Examples and a comparative example.

The glass provided with the coating film was dried at 70° C. for 60 seconds to evaporate the solvent as a liquid medium, and then cured with a high-pressure mercury lamp. In this way, an infrared-absorbing glass in which a coating layer containing infrared-absorbing particles is provided on one surface of a glass substrate is produced.

(3-2) Production of infrared absorbing film Moreover, the coating liquid C1 was coated on the 50-micrometer-thick PET film base material using the bar coater (No. 8), and the coating film was formed. In addition, the same PET film was used when manufacturing an infrared absorption film in other Example and a comparative example.

The PET film provided with the coating film was dried at 70° C. for 60 seconds to evaporate the solvent as a liquid medium, and then cured with a high-pressure mercury lamp. Thus, an infrared absorbing film in which a coating layer containing infrared absorbing particles was provided on one surface of the PET film substrate was produced.

The optical properties of the obtained infrared absorbing transparent substrate were evaluated. Table 3 shows the evaluation results. In addition, in Table 3, when the type of base material is glass, it becomes the evaluation result of infrared-absorbing glass, and when the type of base material is PET, it becomes the evaluation result of infrared-absorbing film.

(3-3) Evaluation of heat resistance and heat and humidity resistance The heat resistance of the infrared-absorbing glass and the heat-and-moisture resistance of the infrared-absorbing film according to Example 1 were evaluated. (3-3-1) Evaluation of heat resistance Visible light transmittance and sunlight transmittance before and after exposure in the infrared absorbing glass according to Example 1 were evaluated.

Table 4 shows the evaluation results. (3-3-2) Evaluation of moisture and heat resistance Visible light transmittance and sunlight transmittance before and after exposure in the infrared absorbing film related to Example 1 were evaluated.

Table 5 shows the evaluation results. (4) Infrared absorption interlayer transparent substrate In addition, to the dispersion B1 which is the infrared absorbing particle dispersion liquid according to Example 1, the dispersant a was further added, and the mass ratio of the dispersant a to the infrared absorbing particles was [dispersant a/infrared absorbing particles]=3. Adjustment. Next, methyl isobutyl ketone was removed from the adjusted dispersion using a spray dryer to obtain an infrared absorbing particle dispersion powder (hereinafter sometimes referred to as "dispersion powder").

A predetermined amount of dispersing powder was added to polycarbonate resin, which is a thermoplastic resin, so that the visible light transmittance of the manufactured infrared absorbing sheet (1.0 mm thickness) became 80%, and a composition for producing an infrared absorbing sheet was prepared.

The composition for producing an infrared absorbing sheet was kneaded at 280° C. using a twin-screw extruder, extruded through a T die, and formed into a 1.0 mm thick sheet by the calender roll method to obtain Example 1. The infrared absorbing sheet involved. In addition, the infrared absorbing sheet is an example of the infrared absorbing particle dispersion.

The obtained infrared absorbing sheet was clamped between two green glass substrates of 100mm×100mm×approximately 2mm thick, heated to 80°C for temporary bonding, and then heated under high pressure at 140°C and 14kg/cm ² Then, the infrared absorbing interlayer transparent substrate is made.

The optical characteristics, heat resistance, and heat-and-moisture resistance of the obtained infrared-absorbing interlayer transparent substrate were evaluated. The evaluation results are shown in Table 6, Table 7, and Table 8. [Example 2] When preparing the infrared absorbing particle dispersion liquid, the pulverization and dispersion time were set to 10 hours. Except for the above points, the same operations as in Example 1 were carried out to obtain powder A2, dispersion liquid B2, infrared-absorbing glass, and infrared-absorbing interlayer transparent substrate according to Example 2. The evaluation results are shown in Tables 1 to 3 and 6. [Example 3] Each powder of tungstic acid (H ₂ WO ₄ ) and cesium carbonate (Cs ₂ CO ₃ ) was weighed at a ratio equivalent to Cs/W (molar ratio)=0.27/1.00, and mixed (mixed process).

The mixed powder was heated under the supply of 5 vol% H ₂ gas with N ₂ gas as the carrier gas, and subjected to a reduction treatment at a temperature of 570° C. for 1 hour (second heat treatment step).

Next, heating was performed under the supply of 1 vol% compressed air using N ₂ gas as a carrier gas, and firing was performed at a temperature of 820° C. for 0.5 hours (first heat treatment step, first step).

Furthermore, it fired at 820 degreeC for 0.5 hour in _N2 gas atmosphere (1st heat treatment process, 2nd step). The pulverization and dispersion time were set to 8 hours.

Except for changing the above points, specifically, the conditions of the mixing step and the heat treatment step when producing infrared absorbing particles, and the conditions of pulverization and dispersion time when preparing the infrared absorbing particle dispersion, the same procedure as in Example 1 was carried out. By operation, powder A3, dispersion liquid B3, infrared-absorbing glass, infrared-absorbing film, and infrared-absorbing interlayer transparent substrate according to Example 3 were manufactured and evaluated. The evaluation results are shown in Tables 1 to 8.

In Examples 4 to 15 and Comparative Examples 1 to 6 described below, the conditions of the mixing step and the heat treatment step when producing infrared absorbing particles, and the conditions of pulverization and dispersion time when preparing an infrared absorbing particle dispersion are partly Or all of the points described later are changed.

The X-ray diffraction pattern of the obtained powder A3 is shown in FIG. 5 . As shown in FIG. 5 , powder A3 was identified as a hexagonal Cs _0.3 (WO ₃ ) (ICDD 01-081-1244) single phase, and was infrared-absorbing particles composed of hexagonal cesium tungsten oxide particles. [Example 4] When preparing infrared-absorbing particles, the mixed powder was heated under the supply of 1 vol% compressed air with N ₂ gas as the carrier gas, and fired at 820° C. for 0.5 hours (first heat treatment step). Next, heating was performed under the supply of 5 vol% H ₂ gas with N ₂ gas as a carrier gas, and firing was performed at a temperature of 570° C. for 1 hour (second heat treatment step, first step). Furthermore, it baked at the temperature of 820 degreeC for 0.5 hour in _N2 gas atmosphere (2nd heat treatment process, 2nd step).

In addition, when preparing the infrared absorbing particle dispersion liquid, the pulverization and dispersion time were set to 8 hours.

Except for the above points, the same operations as in Example 1 were carried out to manufacture and evaluate powder A4, dispersion liquid B4, infrared-absorbing glass, and infrared-absorbing interlayer transparent substrate according to Example 4.

In addition, as shown in Table 1, powder A4 is infrared-absorbing particles composed of particles of composite tungsten oxide having a hexagonal crystal structure.

The evaluation results are shown in Tables 1 to 3 and 6. [Example 5] Each powder of tungstic acid (H ₂ WO ₄ ) and cesium carbonate (Cs ₂ CO ₃ ) was weighed at a ratio equivalent to Cs/W (molar ratio) = 0.33/1.00, and mixed (mixing process ).

The mixed powder was heated under the supply of 5 vol% H ₂ gas with N ₂ gas as the carrier gas, and subjected to a reduction treatment at a temperature of 570° C. for 1 hour (second heat treatment step).

Next, heating is carried out under the supply of ₁ vol% compressed air with N gas as the carrier gas, and firing is carried out at a temperature of 820° C. for _0.5 hour (the first heat treatment process, the first step), and further, under N gas atmosphere , fired at a temperature of 820°C for 0.5 hours (the first heat treatment process, the second step).

When preparing the infrared absorbing particle dispersion liquid, the pulverization and dispersion time were set to 5 hours.

Except for the above points, the same operations as in Example 1 were carried out to manufacture powder A5, dispersion liquid B5, and infrared-absorbing interlayer transparent substrate according to Example 5, and evaluate them.

In addition, as shown in Table 1, powder A5 is infrared-absorbing particles composed of particles of composite tungsten oxide having a hexagonal crystal structure.

The evaluation results are shown in Table 1, Table 2, and Table 6. [Example 6] Each powder of tungstic acid (H ₂ WO ₄ ) and cesium carbonate (Cs ₂ CO ₃ ) was weighed at a ratio equivalent to Cs/W (molar ratio) = 0.32/1.00, and mixed (mixing process ).

The mixed powder was heated under the supply of 5 vol% H ₂ gas with N ₂ gas as the carrier gas, and subjected to a reduction treatment at a temperature of 570° C. for 1 hour (second heat treatment step).

Next, heating is carried out under the supply of ₁ vol% compressed air with N gas as the carrier gas, and firing is carried out at a temperature of 820° C. for _0.5 hour (the first heat treatment process, the first step), and further, under N gas atmosphere Baking was carried out at a temperature of 820°C for 0.5 hours (first heat treatment step, second step).

When preparing the infrared absorbing particle dispersion liquid, the pulverization and dispersion time were set to 5 hours.

Except for the above points, the same operations as in Example 1 were carried out to manufacture and evaluate powder A6, dispersion liquid B6, and infrared-absorbing interlayer transparent base material according to Example 6.

In addition, as shown in Table 1, powder A6 is infrared-absorbing particles composed of particles of composite tungsten oxide having a hexagonal crystal structure.

The evaluation results are shown in Table 1, Table 2, and Table 6. [Example 7] Each powder of tungstic acid (H ₂ WO ₄ ) and cesium carbonate (Cs ₂ CO ₃ ) was weighed at a ratio equivalent to Cs/W (molar ratio) = 0.31/1.00, and mixed (mixing process ).

The mixed powder was heated under the supply of 5 vol% H ₂ gas with N ₂ gas as the carrier gas, and subjected to a reduction treatment at a temperature of 570° C. for 1 hour (second heat treatment step).

Next, heating is carried out under the supply of ₁ vol% compressed air with N gas as the carrier gas, and firing is carried out at a temperature of 820° C. for _0.5 hour (the first heat treatment process, the first step), and further, under N gas atmosphere , fired at a temperature of 820°C for 0.5 hours (the first heat treatment process, the second step).

When preparing the infrared absorbing particle dispersion liquid, the pulverization and dispersion time were set to 5 hours.

Except for the above points, the same operations as in Example 1 were carried out to manufacture and evaluate powder A7, dispersion liquid B7, and infrared-absorbing interlayer transparent substrate according to Example 7.

In addition, as shown in Table 1, powder A7 is infrared-absorbing particles composed of particles of composite tungsten oxide having a hexagonal crystal structure.

The evaluation results are shown in Table 1, Table 2, and Table 6. [Example 8] Each powder of tungstic acid (H ₂ WO ₄ ) and cesium carbonate (Cs ₂ CO ₃ ) was weighed at a ratio equivalent to Cs/W (molar ratio) = 0.30/1.00, and mixed (mixing process ).

The mixed powder was heated under the supply of 5 vol% H ₂ gas with N ₂ gas as the carrier gas, and subjected to a reduction treatment at a temperature of 570° C. for 1 hour (second heat treatment step).

Next, heating is carried out under the supply of ₁ vol% compressed air with N gas as the carrier gas, and firing is carried out at a temperature of 820° C. for _0.5 hour (the first heat treatment process, the first step), and further, under N gas atmosphere , fired at a temperature of 820°C for 0.5 hours (the first heat treatment process, the second step).

When preparing the infrared absorbing particle dispersion liquid, the pulverization and dispersion time were set to 5 hours.

Except for the above points, the same operations as in Example 1 were carried out to manufacture and evaluate powder A8, dispersion liquid B8, and infrared-absorbing interlayer transparent substrate according to Example 8.

In addition, as shown in Table 1, powder A8 is infrared-absorbing particles composed of particles of composite tungsten oxide having a hexagonal crystal structure.

The evaluation results are shown in Table 1, Table 2, and Table 6. [Example 9] Each powder of tungstic acid (H ₂ WO ₄ ) and cesium carbonate (Cs ₂ CO ₃ ) was weighed at a ratio equivalent to Cs/W (molar ratio) = 0.29/1.00, and mixed (mixing process ).

The mixed powder was heated under the supply of 5 vol% H ₂ gas with N ₂ gas as the carrier gas, and subjected to a reduction treatment at a temperature of 570° C. for 1 hour (second heat treatment step).

Next, heating is carried out under the supply of ₁ vol% compressed air with N gas as the carrier gas, and firing is carried out at a temperature of 820° C. for _0.5 hour (the first heat treatment process, the first step), and further, under N gas atmosphere Baking was carried out at a temperature of 820°C for 0.5 hours (first heat treatment step, second step).

When preparing the infrared absorbing particle dispersion liquid, the pulverization and dispersion time were set to 5 hours.

Except for the above points, the same operations as in Example 1 were carried out to manufacture and evaluate powder A9, dispersion liquid B9, and infrared-absorbing interlayer transparent substrate according to Example 9. In addition, the mixing process is the same condition as Example 1, and it describes for confirmation.

In addition, as shown in Table 1, powder A9 is infrared-absorbing particles composed of particles of composite tungsten oxide having a hexagonal crystal structure.

The evaluation results are shown in Table 1, Table 2, and Table 6. [Example 10] Each powder of tungstic acid (H ₂ WO ₄ ) and cesium carbonate (Cs ₂ CO ₃ ) was weighed at a ratio equivalent to Cs/W (molar ratio) = 0.28/1.00, and mixed (mixing process ).

The mixed powder was heated under the supply of 5 vol% H ₂ gas with N ₂ gas as the carrier gas, and subjected to a reduction treatment at a temperature of 570° C. for 1 hour (second heat treatment step).

Next, heating is carried out under the supply of ₁ vol% compressed air with N gas as the carrier gas, and firing is carried out at a temperature of 820° C. for _0.5 hour (the first heat treatment process, the first step), and further, under N gas atmosphere , fired at a temperature of 820°C for 0.5 hours (the first heat treatment process, the second step).

When preparing the infrared absorbing particle dispersion liquid, the pulverization and dispersion time were set to 5 hours.

Except for the above points, the same operations as in Example 1 were carried out to manufacture and evaluate powder A10, dispersion liquid B10, and infrared-absorbing interlayer transparent substrate according to Example 10.

In addition, as shown in Table 1, powder A10 is infrared-absorbing particles composed of particles of composite tungsten oxide having a hexagonal crystal structure.

The evaluation results are shown in Table 1, Table 2, and Table 6. [Example 11] Each powder of tungstic acid (H ₂ WO ₄ ) and cesium carbonate (Cs ₂ CO ₃ ) was weighed at a ratio equivalent to Cs/W (molar ratio) = 0.26/1.00, and mixed (mixing process ).

The mixed powder was heated under the supply of 5 vol% H ₂ gas with N ₂ gas as the carrier gas, and subjected to a reduction treatment at a temperature of 570° C. for 1 hour (second heat treatment step).

Next, heating is carried out under the supply of ₁ vol% compressed air with N gas as the carrier gas, and firing is carried out at a temperature of 820° C. for _0.5 hour (the first heat treatment process, the first step), and further, under N gas atmosphere , fired at a temperature of 820°C for 0.5 hours (the first heat treatment process, the second step).

When preparing the infrared absorbing particle dispersion liquid, the pulverization and dispersion time were set to 5 hours.

Except for the above points, the same operations as in Example 1 were carried out to manufacture and evaluate powder A11, dispersion liquid B11, and infrared-absorbing interlayer transparent substrate according to Example 11.

In addition, as shown in Table 1, powder A11 is infrared-absorbing particles composed of particles of composite tungsten oxide having a hexagonal crystal structure.

The evaluation results are shown in Table 1, Table 2, and Table 6. [Example 12] Each powder of tungstic acid (H ₂ WO ₄ ) and cesium carbonate (Cs ₂ CO ₃ ) was weighed at a ratio equivalent to Cs/W (molar ratio) = 0.27/1, and mixed (mixing process ).

The mixed powder was heated under the supply of 5 vol% H ₂ gas with N ₂ gas as the carrier gas, and subjected to a reduction treatment at a temperature of 570° C. for 1 hour (second heat treatment step).

Next, heating was performed under the supply of 1 vol % compressed air with N ₂ gas as the carrier gas, and firing was carried out at a temperature of 820° C. for 1 hour (first heat treatment step, first step).

Furthermore, it fired at 820 degreeC for 0.5 hour in _N2 gas atmosphere (1st heat treatment process, 2nd step).

When preparing the infrared absorbing particle dispersion liquid, the pulverization and dispersion time were set to 8 hours.

Except for the above points, the same operation as in Example 1 was carried out to manufacture and evaluate powder A12 and dispersion liquid B12 according to Example 12.

In addition, as shown in Table 1, powder A12 is infrared-absorbing particles composed of particles of composite tungsten oxide having a hexagonal crystal structure.

The evaluation results are shown in Table 1 and Table 2. [Example 13] Each powder of tungstic acid (H ₂ WO ₄ ) and cesium carbonate (Cs ₂ CO ₃ ) was weighed at a ratio equivalent to Cs/W (molar ratio) = 0.27/1, and mixed (mixing process ).

The mixed powder was heated under the supply of 5 vol% H ₂ gas with N ₂ gas as the carrier gas, and subjected to a reduction treatment at a temperature of 570° C. for 1 hour (second heat treatment step).

Next, heating was performed under the supply of 1 vol% compressed air with N ₂ gas as the carrier gas, and firing was carried out at a temperature of 820° C. for 1.5 hours (first heat treatment step, first step).

Furthermore, it fired at 820 degreeC for 0.5 hour in _N2 gas atmosphere (1st heat treatment process, 2nd step).

When preparing the infrared absorbing particle dispersion liquid, the pulverization and dispersion time were set to 8 hours.

Except for the above points, the same operations as in Example 1 were carried out to manufacture and evaluate powder A13 and dispersion liquid B13 according to Example 13.

In addition, as shown in Table 1, powder A13 is infrared-absorbing particles composed of particles of composite tungsten oxide having a hexagonal crystal structure.

The evaluation results are shown in Table 1 and Table 2. [Example 14] Each powder of tungstic acid (H ₂ WO ₄ ) and cesium carbonate (Cs ₂ CO ₃ ) was weighed at a ratio equivalent to Cs/W (molar ratio) = 0.27/1, and mixed (mixing process ).

The mixed powder was heated under the supply of 5 vol% H ₂ gas with N ₂ gas as the carrier gas, and subjected to a reduction treatment at a temperature of 570° C. for 1 hour (second heat treatment step).

Next, heating was performed under the supply of 1 vol% compressed air with N ₂ gas as the carrier gas, and firing was carried out at a temperature of 820° C. for 45 minutes (first heat treatment step, first step).

Furthermore, it baked at the temperature of 820 degreeC for 15 minutes in _N2 gas atmosphere (1st heat treatment process, 2nd step).

When preparing the infrared absorbing particle dispersion liquid, the pulverization and dispersion time were set to 8 hours.

Except for the above points, the same operations as in Example 1 were carried out to manufacture and evaluate powder A14 and dispersion liquid B14 according to Example 14.

In addition, as shown in Table 1, powder A14 is infrared-absorbing particles composed of particles of composite tungsten oxide having a hexagonal crystal structure.

The evaluation results are shown in Table 1 and Table 2. [Example 15] Each powder of tungstic acid (H ₂ WO ₄ ) and cesium carbonate (Cs ₂ CO ₃ ) was weighed at a ratio equivalent to Cs/W (molar ratio) = 0.27/1, and mixed (mixing process ).

The mixed powder was heated under the supply of 5 vol% H ₂ gas with N ₂ gas as the carrier gas, and subjected to a reduction treatment at a temperature of 570° C. for 1 hour (second heat treatment step).

Next, heating was performed under the supply of 1 vol % compressed air with N ₂ gas as the carrier gas, and firing was carried out at a temperature of 820° C. for 2 hours (first heat treatment step, first step).

When preparing the infrared absorbing particle dispersion liquid, the pulverization and dispersion time were set to 8 hours.

Except for the above points, the same operation as in Example 1 was carried out to manufacture and evaluate powder A15 and dispersion liquid B15 according to Example 15.

In addition, as shown in Table 1, powder A15 is infrared-absorbing particles composed of particles of composite tungsten oxide having a hexagonal crystal structure.

The evaluation results are shown in Table 1 and Table 2. [Example 16] Using the dispersion B3 related to Example 3, prepare 0.15% by mass of cesium tungsten oxide particles as infrared absorbing particles, 73.0% by mass of polyvinyl butyral resin (PVB), triethylene glycol di- A composition comprising 26.85% by mass of 2-ethylhexanoate (3GO). Then, this composition was kneaded with a twin-screw extruder, extruded from a T-die, and formed into a sheet having a thickness of 0.16 mm by a calender roll method to obtain an infrared absorbing sheet according to Example 16.

The infrared-absorbing interlayer transparent substrate according to Example 16 was obtained in the same manner as in Example 1, except that the obtained infrared-absorbing sheet was sandwiched between two 100 mm×100 mm×3 mm-thick glass substrates.

Table 9 shows the evaluation results of the obtained infrared-absorbing interlayer transparent substrate. [Comparative Example 1] Each powder of tungstic acid (H ₂ WO ₄ ) and cesium carbonate (Cs ₂ CO ₃ ) was weighed at a ratio equivalent to Cs/W (molar ratio) = 0.33/1.00, and mixed (mixing process ).

The mixed powder obtained in the mixing step was heated under the supply of 5 vol% H ₂ gas with N ₂ gas as the carrier gas, and a reduction treatment was performed at a temperature of 570° C. for 1 hour.

Next, it was fired at a temperature of 820° C. for 1 hour in a N ₂ gas atmosphere. In addition, the process corresponding to the 1st step of the 1st heat treatment process in Example 1 was not implemented.

When preparing the infrared absorbing particle dispersion liquid, the pulverization and dispersion time were set to 10 hours.

Except for the above points, the same operations as in Example 1 were carried out to obtain powder A21, dispersion liquid B21, infrared-absorbing glass, infrared-absorbing film, and infrared-absorbing interlayer transparent substrate according to Comparative Example 1. Moreover, the measurement of the XRD pattern was performed about the obtained powder A21. The evaluation results are shown in FIG. 6 and Tables 1 to 8. [Comparative Example 2] When preparing infrared-absorbing particles, the mixed powder was heated at 820° C. for 0.5 hours under the supply of 1 vol % compressed air with N ₂ gas as the carrier gas. In addition, the process corresponding to the second step of the second heat treatment step in Example 1 and the second step of the first heat treatment step was not carried out.

When preparing the infrared absorbing particle dispersion liquid, the pulverization and dispersion time were set to 8 hours.

Except for the above points, the same operations as in Example 1 were carried out to obtain powder A22, dispersion liquid B22, and infrared-absorbing glass according to Comparative Example 2. Moreover, the measurement of the XRD pattern was performed about the obtained powder A22. The evaluation results are shown in FIG. 6 and Tables 1 to 3. [Comparative Example 3] Each powder of tungstic acid (H ₂ WO ₄ ) and cesium carbonate (Cs ₂ CO ₃ ) was weighed at a ratio equivalent to Cs/W (molar ratio)=0.27/1.00, and mixed. Except for the above points, the same operation as in Comparative Example 1 was carried out to obtain powder A23 and dispersion liquid B23 according to Comparative Example 3. The evaluation results are shown in Table 1 and Table 2. [Comparative Example 4] Each powder of tungstic acid (H ₂ WO ₄ ) and cesium carbonate (Cs ₂ CO ₃ ) was weighed at a ratio equivalent to Cs/W (molar ratio)=0.26/1.00, and mixed. Except for the above, the same operation as in Comparative Example 1 was carried out, and powder A24 and dispersion liquid B24 related to Comparative Example 4 were obtained. The evaluation results are shown in Table 1 and Table 2. [Comparative Example 5] Each powder of tungstic acid (H ₂ WO ₄ ) and cesium carbonate (Cs ₂ CO ₃ ) was weighed at a ratio corresponding to Cs/W (molar ratio)=0.25/1.00, and mixed. Except for the above points, the same operation as in Comparative Example 1 was carried out to obtain powder A25 and dispersion liquid B25 according to Comparative Example 5. The evaluation results are shown in Table 1 and Table 2. [Comparative Example 6] Each powder of tungstic acid (H ₂ WO ₄ ) and cesium carbonate (Cs ₂ CO ₃ ) was weighed at a ratio equivalent to Cs/W (molar ratio)=0.20/1.00, and mixed. Except for the above points, the same operation as in Comparative Example 1 was carried out to obtain powder A26 and dispersion liquid B26 according to Comparative Example 6. The evaluation results are shown in Table 1 and Table 2. [Comparative Example 7] An infrared-absorbing interlayer transparent substrate according to Comparative Example 7 was obtained in the same manner as in Example 16 except that the dispersion liquid B21 related to Comparative Example 1 was used.

Table 9 shows the evaluation results of the obtained infrared-absorbing interlayer transparent substrate. [Reference example 1] Instead of powder A1, tin-doped indium oxide powder manufactured by NYACOL was used to prepare powder A30.

Moreover, except having used such powder A30, it carried out similarly to Example 1, and obtained the dispersion liquid B30 which concerns on reference example 1. The evaluation results are shown in Table 1 and Table 2.

[Table 1]

[Table 2]

[table 3]

[Table 4]

[table 5]

[Table 6]

[Table 7]

[Table 8]

[歸納] 由各評價結果明確能夠確認，實施例1～實施例15涉及的紅外線吸收粒子具有六方晶的晶體結構，為具有規定的組成的複合鎢氧化物的粒子。 [Table 9]

[Summary] From the evaluation results, it can be clearly confirmed that the infrared absorbing particles according to Examples 1 to 15 have a hexagonal crystal structure and are composite tungsten oxide particles having a predetermined composition.

In addition, the infrared-absorbing particle concentration when the visible light transmittance in the infrared-absorbing particle dispersion is 80% is set to be 0.05% by mass or more and 0.20% by mass or less. Furthermore, b ^* of the infrared-absorbing particle dispersions of Examples 1 to 15 was greater than 0, and thus it was confirmed that the infrared-absorbing particles contained in the infrared-absorbing particle dispersions were light blue. Furthermore, it can be confirmed that the light transmittance at 850 nm of the infrared-absorbing interlayer transparent substrates of Examples 1-3 and 16 is as high as 30% or more, which is also higher than that of Comparative Examples 1 and 7. That is, it can be confirmed that the signal transmittance of mobile phones and various sensors is high, and the detection accuracy of various sensors is improved.

With respect to the infrared-absorbing transparent substrate subjected to the evaluation of the colorimetric system, it was confirmed that b ^* >0 in the L ^* a ^* b ^* colorimetric system. Furthermore, it can be confirmed that the heat-resistant Δ sunlight transmittance of the infrared-absorbing transparent substrates of Examples 1 and 3 evaluated for weather resistance is 1.0% or less, and the heat-and-moisture resistance Δ sunlight transmittance is less than 2.0%. The infrared transparent base material of 1 is superior in weather resistance.

In addition, the infrared-absorbing transparent substrates of other examples that did not show evaluation results showed the same tendency in the weather resistance evaluation.

That is, in Examples 1 to 15, it was confirmed that infrared-absorbing particles having a light blue color and excellent weather resistance and infrared-absorbing properties were obtained.

On the other hand, the infrared-absorbing particles involved in Comparative Examples 1, 3 to 6 have a hexagonal crystal structure, but the color tone at the time of light absorption by only the infrared-absorbing particles in the infrared-absorbing particle dispersion liquid is calculated at L ^* a ^* b ^* b ^* <0 in the color system. In addition, the infrared-absorbing particles involved in Comparative Example 2 are a mixture of materials having crystal structures other than hexagonal crystals. As can be seen from the evaluation results of the infrared-absorbing particle dispersion shown in Table 2, it can be said that the solar transmittance is high, and the infrared ray transmittance is high. Poor absorption characteristics.

This application claims priority based on Japanese Patent Application No. 2021-060997 filed on March 31, 2021, and Japanese Patent Application No. 2021-140530 filed on August 30, 2021, and Japanese Patent Application No. 2021- The entire contents of No. 060997 and Japanese Patent Application No. 2021-140530 are incorporated in this international application.

10: Infrared Absorbing Particle Dispersion 11, 21: Infrared absorbing particles 12: liquid medium 20, 32: Infrared absorbing particle dispersion 22: Solid medium 30: Infrared absorption interlayer transparent substrate 311, 312, 41: transparent substrate 40: Infrared absorbing transparent substrate 41A: one side 42: Infrared absorbing layer

[ Fig. 1 ] is a schematic diagram of a dispersion liquid of infrared absorbing particles. [ Fig. 2 ] is a schematic diagram of a dispersion of infrared absorbing particles. [ Fig. 3 ] is a schematic cross-sectional view of an infrared-absorbing interlayer transparent substrate. [ Fig. 4 ] is a schematic cross-sectional view of an infrared-absorbing transparent substrate. [ Fig. 5 ] is an XRD pattern of infrared absorbing particles obtained in Example 3. [ FIG. 6 ] is an XRD pattern of infrared-absorbing particles obtained in Comparative Examples 1 and 2. [ FIG.

10: Infrared Absorbing Particle Dispersion

11: Infrared absorbing particles

12: liquid medium

Claims (18)

An infrared-absorbing particle, which is an infrared-absorbing particle containing composite tungsten oxide particles, the composite tungsten oxide particle has a hexagonal crystal structure, and is a composite tungsten oxide particle expressed by the general formula M _x W _y O _z , Among them, M is one or more elements selected from Cs, Rb, K, Tl, Ba, Ca, Sr, Fe, W is tungsten, O is oxygen, 0.25≦x/y≦0.39, 2.70≦z/y ≦2.90. The infrared absorbing particle according to claim 1, wherein the surface thereof is coated with a compound containing one or more atoms selected from Si, Ti, Zr, and Al. A dispersion of infrared absorbing particles, which contains: liquid medium, and The infrared-absorbing particles of claim 1 or 2 disposed in the liquid medium. The infrared-absorbing particle dispersion according to claim 3, wherein, The average dispersed particle diameter of the infrared absorbing particles is not less than 1 nm and not more than 800 nm. The infrared-absorbing particle dispersion according to claim 3 or 4, wherein, The liquid medium is one selected from the liquid medium material group consisting of water, organic solvent, grease, liquid resin and plastic plasticizer, or two selected from the liquid medium material group a mixture of the above. The infrared-absorbing particle dispersion according to any one of Claims 3 to 5, This infrared absorbing particle dispersion liquid contains a dispersant. The infrared-absorbing particle dispersion according to any one of Claims 3 to 6, It contains 0.001 mass % or more and 80.0 mass % or less of the said infrared-absorbing particle|grains. The infrared-absorbing particle dispersion according to any one of claims 3 to 7, wherein the color tone when calculating light absorption by the infrared-absorbing particles alone is b ^* >0 in the L ^* a ^* b ^* color system. The infrared-absorbing particle dispersion according to any one of Claims 3 to 8, When the visible light transmittance is 80%, the concentration of the infrared absorbing particles is not less than 0.05% by mass and not more than 0.20% by mass. A dispersion of infrared absorbing particles having: solid media, and The infrared-absorbing particles of claim 1 or 2 arranged in the solid medium. In the infrared absorbing particle dispersion according to Claim 10, the color tone when calculating light absorption by the infrared absorbing particles alone is b ^* >0 in the L ^* a ^* b ^* color system. The infrared-absorbing particle dispersion according to claim 10 or 11, wherein, The solid medium contains thermoplastic resin or UV curable resin. The infrared-absorbing particle dispersion according to claim 12, wherein, The thermoplastic resin is selected from polyethylene terephthalate resin, polycarbonate resin, acrylic resin, styrene resin, polyamide resin, polyethylene resin, vinyl chloride resin, olefin resin, epoxy resin, One resin in the resin group consisting of polyimide resin, fluororesin, ethylene-vinyl acetate copolymer, and polyvinyl acetal resin, a mixture of two or more resins selected from the resin group, Or a copolymer of two or more resins selected from the group of resins. The infrared-absorbing particle dispersion according to any one of Claims 10 to 13, It has a sheet shape, a plate shape or a film shape. A kind of infrared absorption interlayer transparent base material, it has: a plurality of sheets of transparent substrate, and The infrared-absorbing particle dispersion according to any one of claims 10 to 14, The infrared-absorbing particle dispersion has a laminated structure arranged between a plurality of the transparent substrates. Such as the infrared absorption interlayer transparent substrate of claim 15, The light transmittance of its wavelength 850nm is more than 30%. A kind of infrared absorption transparent base material, it has: transparent substrates, and an infrared absorbing layer disposed on at least one side of the transparent substrate, The infrared absorbing layer is the infrared absorbing particle dispersion according to any one of Claims 10 to 14. Such as the infrared-absorbing transparent substrate of claim 17, The light transmittance of its wavelength 850nm is more than 30%.

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